Tube cracking furnace



' A118- 221950 J. B. oRR, JR 2,519,696

TUBE CRACKING FURNACE original Filed Aug. 27, `1942 4 sheetssheet 1 KTM NVENTOR Aug; 22, 1950 .1. B. oRR, JR 2,519,696

TUBE CRACKING FURNACE Original Filed Aug. 27, 1942 Sheets-Sheet 2 Patented Aug. 22, 1950 UNITED STATES ATENT OFFICE Continuation of application Serial No. 456,437",`

August 2*7; 1942. This application July 29', 1949,'

SerialN: 10573649 This i is a continuation: of. myl application Serial No'. 4156,43? of` August 27., 1942; now abandoned, -infavon of the present application.y

'Ihis invention pertains tostill or large-multiple tube` cracking apparatus, and moreparticularly, to-.an improved combination of cracking` tubes in; a furnace construction.

Inf another aspect, my invention pertainsI to apparatus; for producing; hydrocarbons, particularly; gaseous unsaturated hydrocarbons Where rela-tivelyy high temperatures are required;

Although the apparatus of` they present inventionihas been designed. particularly and. is-to be preferably used for the production. ofl unsaturated gaseous hydrocarbonsfromsaturatedz gaseous hydrocarbons employing an endothermic procesaitf will be apparent to those skilled-inthe arttthat. other suitable uses-v. may ber made of the. same and of the novel, principles: involved therein.`

Large quantities o'fnatural gas are available in the various oil fields of'this country. But-heretofore', no one has been able to provide what may be .termedapractical procedure for utilizing such natural gas' in the4 production of more desirable g,

gases. and. especially those of an unsaturated nature 4Isuch as acetyleneandthe ethylene'series. The `problem of; providing a suitable cracking tube arrangementy thatwill withstand `the temperatures involved is avery important. one and particularly if the process is tobe carried out cna c.on'imeroialv basis,y namely, substantially continuously. Another important factor rests upon the-necessity of? what maybe termedv economic production.of.r desired gaseousI products from` a givenouantity of natural gas.

Inviewa of the above andother considerations, ithas beenranobject. of my inventionto provide new.. andimprcved procedure-for producing unsaturated hydrocarbons, and particularly, unsaturatedgaseous hydrocarbons, by endothermic treatment of saturated hydrocarbons.

Another object has been to devise a multiple apparatus arrangement for, in a practical manner7 producing suitable desired gaseous-hydrocarbons by thermal treatmentthereof.

A.further object of myinventionhas been'to provide a new and improved form of cracking furnace or still suitable for utilizing large: quantitiesof` natural, gas to yproduce correspondingly large quantities of desired, gases.

Th.ese'-and ,manyother objects of'my invention Will appear to those skilled in the art-.from-lthe description, the. drawingaand thefclaimsg, as well, asafrom thprior Aartv backgroundr 1e Claims. (c1. ,2a- 21.7

`the hottest zone ofc. thev cracking chambers.

In the drawings:`

Figure 1 is a vertical-'longitudinal section in eleva-tion throughl an. apparatus constructed) in accordance withA myl invention' and taken along the line I'l of Figure 2:;

Figure 2.- is an end View in elevation taken from therighttof the'embodiment of Figurel;

Figure 3: is a horizontall section. taken.` along the lineAIlI-'Illv of Figure 2;. and

Figureri; is an enlargedisectional detail show-- ing aA cooling arrangement-'for outlet tubesy that may be utilized.4 in connection with the appara-1 tus.- shownin/Figures 1.--3,` inclusive Figure 5 isa` vertical.Y section in elevation through aiv single tube` cracking assembly embodying my invention;

Figure 6is a similar. View of amodied arrangement employingamu1ti+tubeassembly- By reference toeligurez4 of.- the drawings; it

vWill benoted that'I havey grouped a series or set of cracking tubes` designated l5v about an outlet tube designed:` 16, in suchfa manner` as to provide asubstantial equidistant .ovaofthe gases being exhausted from the apparatus. Suchgases may-consistv of combustible.. gases, steam, inert gases; cracked. gases, etc.

`Steam and air used tor. combustion purposes may. be` preliminarilyy preheated. before. being.. intrcduced: intol theapparatus... But as show-n. in Figure l; uponentry through inlet IIJ', they are, inanyw event, preheated byy movement. aboutcoinbustionchamber portions of thefcracking. tubes before they enterV av mixing chamber Il Within which fthey are :combined `Withcombustible gases, and thus, before the mixture is introduced into the cracking tubes: l5.`

The gases to. be cracked are-preferably.y introducedat anopposite end of.. the. cracking tubes in such amanner that they are preferably preliminarily heated by, gases in the cracking chamber before they come into.directlfcontactwith In other words, the gases-toibo cracked. are preferably'introducedzby some suitable. means. such as pipe i4 that extends.. along. and substantially concentrically of the, particular cracking chamber involved upto the hotter. portions` and downstream of checker-brick l2, insucha manner that the gases to be'crackedcomeinto direct thermal or heatexchange.admiXture with the hotburnt gases.'

Referring particularly. to the drawings, ,a represents the combustible gas tobe burntifor heating purposes grepresentsair. or. air and steam to be ,mxedwith thecombustible gasv and. to be apart wall portions Ia and I8c.

utilized in the process of combustion. As touched upon above, the air and steam are preferably preheated to a suitable temperature such as 1100* C. before being introduced through inlet I0 along passageways about each of the cracking tubes I5; the purpose is to lighten the heat exchange load of the outer portions of the tubes I5. B represents the same air and gas after it has been further heated to substantially 1200o C'. by movement about combustion chamber portions of the cracking tubes. E represents the burnt gases and steam, C represents entering gas or hydrocarbons to be cracked, such as natural gas, and D represents the exhausting gaseous mixture of cracked gases, :burnt gases, steam, etc.

Combustible gases after being introduced through inlet tubes Il mix with the heated air and steam B in a mixing chamber II and then enter each of the plurality of cracking tubes I5, passing through checkerbrick portions I2 and being burnt within the combustion chambers (to the left of portions I2 in Figure 1), The mixing chamber Il comprises a metal-encased insulated steam box or wall portion |811 fastened in an airtight manner against front brickwork portion I8a. An exhaust chamber Il' of similar construction is defined by wall portion I 3d that is fastened in an airtight manner against the back lbrickwork portion E80. As will be noted, the three brickwork portions Ia, I8, and I8c are positioned in a spaced-apart relationship in such a manner as to, in effect, provide two circulating chambers for movement of gases about the cracking tubes I5. This provides a maximum efciency 'of utilization of the various materials involved,

as well as a maximum life of the tubes and a retention of a suitable temperature of endothermic treatment without injury to the cracking tubes, all irrespective of the fact that these tubes lare mounted in a rather closely adjacent relationship within the apparatus.

Referring to Figure 1 of the drawings, it is seen that the metal-encased box or enclosure Ib extends about the wall or brickwork portion I8a to provide a uid connection or passageway for the portion of the combustion iiuid, see the arrows B, which enters through the supplemental combustion fluid inlet Ill in a bottom enclosing portion IBc and flows around exterior portions of (laterally with respect to the axes of) the re- -action tubes I5 into the front chamber, see the arrows B'. This supplemental fluid mixes with another portion of the combustion fluid that is introduced through the combustion iiuid inlets or tubes Il.

kIt will be also noted that the combustion fluid Vinlet tubes II extend through and are positioned or supported by the enclosure I 8b. The tubes 'II are of smaller diameter than the reaction tubes I5, have ends that are open to the front chamber, and that are in a substantially spacedapart axial-alignment with the combustion uid inlet opening at the front end of each associated reaction tube I5. The intermediate wall portion I 8 provides a pair of chambers about exterior wall portions of the reaction tubes with the spaced- As indicated above, a portion of the combustion gases, such as air and steam, enter through the bottom cornrbustion fluid inlet I0 into the chamber formed between the spaced walls |301r and I8 and move upwardly over and about the exterior walls of the reaction tubes to take up heat from the tubes before they enter the frontal, `or combustion fluid `mixing chamber; it is thus apparent @har the chamber between walls I 8a and I8 may be termed a heat exchange chamber.

As shown particularly in Figure 4, the outlet tubes I'B are preferably water-jacketed. This helps in at least prelminarily and quickly cooling the gaseous exhaust mixture and preventing polymerization and other undesired side reactions. In this gure, 2 Ia indicates a water inlet pipe and 2lb indicates a water outlet pipe of any suitable circulatory system. As shown in this figure, the exhaust fluid outlet tubes I6 are preferably of the same length, see Figure 4 of the drawings, and also page 4, lines 13 to 17 of my application Serial No. 456,434, now abancloned, and have spaced-apart or jacketed wall portions I6 which define a cooling chamber.

Referring particularly to Figure 5, the gases are cracked in a suitable longitudinallyeextending tube 2U having tube wall portions surmounted vby refractory wall portions 26, 26a, and 26h. Air

and steam for effecting combustion may be introduced through inlet IlarI and combustion gas through inlet II into an inlet mixing chamber 23. Such gases after being introduced in a suitable relationship enter a combustion chamber portion 2l! where they are fired and heat checkerwork portions I2 at what may be termed the forward or inlet end of the refractory tube 2U. Gaseous feed hydrocarbons such as natural gas that are to be cracked are introduced through inlet pipe 28 at the discharge end of the tube 20. It will be noted that this inlet pipe extends through a rear chamber 29 and a substantial distance into and in a substantially axially aligned relationship along or substantially concentrically of the outlet end of the refractory tube 20.

In accordance with my invention, the gaseous hydrocarbons from pipe 28 mix somewhat turbulently with combustion gases in the form of a superheated fluid in the portion 2'! in such a manner that the heat of the combustion gases 'cracks or endothermically converts the gaseous hydrocarbons into desired unsaturated hydrocarbon such as acetylene or ethylene or those of the ethylene series. rlhe hot cracked gases leave the refractory tube through the outlet chest or chamber 2s and pipe 3 conducts them to a suitable water condenser and stripping plant installation. It will be apparent that the gases to be cracked or heated, at least initially, flow or move counter to the heating fluid, mix with such iiuid, and then iow toward the chest 29. In this manner, a maximum thermal heat exchange relationship is provided in that the gases to be cracked are preliminarily heated before they are subjected to maximum heat and direct admixture in the chamber porti-on 2l. The tube 28 also aids in quickly cooling the cracked gases and preventing undesired side reactions as well as polymerization of the acetylene. The inlet and outlet chest or chamber portions 23 and 29 aid in increasing the thermal eiiiciency of the cracking or reaction tube IS. An effective admixture of the gases is accomplished by reason -of turbulence existing at the inner end of the supply tube 28. The arrangement also provides for a maxiymum control of treatment to effect optimum results.

In the drawing of Figure 6, I have endeavored -to avoid unnecessary repetition by referring to parts that are substantially similar to those specified in the description of Figure 5 by the same numerals.

In Figure 6, gas is introduced by pipe 22 through a plurality of branches a, b, and c, into inlet chest What I claim is:

l. A furnace for thermally converting normally gaseous hydrocarbons into other hydrocarbons comprising a plurality of horizontally extending reaction tubes supported by and positioned in separated refractory walls, a first wall of said separated supporting walls at one end of said tubes and a second of said walls together with said first wall dening a vertical passageway about the exterior portions of said tubes, a front enclosing wall for said furnace separated from said rst supporting wall and extending so as to form a relatively narrow frontal chamber into lwhich said tubes open and which communicates at the top thereof with said vertical passageway, a third wall of said supporting walls at the opposite ends of said tubes and a rear enclosing vwall for the furnace defining a relatively narrow rear chamber into which said tubes open, a plurality of inlets into said first chamber, an inlet into the bottom of said vertical passageway, a plurality of small outlets from said rear chamber, and pipes extending through said rear chamber and for a substantial distance into said tubes and concentrically arranged therein. 2. A furnace for thermally converting normally fluid hydrocarbons into other hydrocarbons comprising a plurality of reaction tubes extending in substantially the same direction supported by and positioned in separated refractory walls, a

first Wall of said separated supporting Walls adjacent one end of said tubes, a second of said walls together with said first wall defining a passageway extending in another direction about the exterior portions of said tubes, a front enclosing wall for said furnace separated from said first supporting wall and extending so as to form a frontal chamber into which said tubes open and which communicates adjacent one end thereof with said passageway, a third wall of 'said supporting walls at the opposite ends of said tubes, a rear enclosing wall for the furnace defining a rear chamber into which said tubes open, a plurality of inlets into said first chamber, an inlet into said passageway adjacent another end thereof, a plurality of outlets from said rear chamber, and tubes of smaller diameter than said reaction tubes extending through said rear chamber and for a substantial distance into said tubes and concentrically arranged therein.

3. A furnace as defined in claim 2 wherein each of said plurality of inlets is a tube positioned to extend into said first chamber in substantial axial alignment with a corresponding reaction tube of said plurality of reaction tubes.

4, Thermal furnace apparatus suitable for continuously converting uid hydrocarbons into other hydrocarbons comprising, a plurality of reaction tubes, spaced-apart supporting wall portions within which said reaction tubes are positioned, one of said Wall portions being located adjacent one end of each of said reaction tubes, a second of said wall portions being located adjacent the other end of each of said reaction tubes, a third of said Wall portions being located 'intermediate said first and second-mentioned wall portions and defining a heat exchange chamber with said first-mentioned wall portion, said third-mentioned wall portion defining a second chamber about exterior portions of said tubes with said second-mentioned wall portions, en-

closing portions across said second and third- `mentioned supporting wall portions, enclosing portions across said first and third-mentioned supporting wall portions, a portion of said last- `mentioned enclosing portionsA extending in a spaced relationship about one endv of and along said first-mentioned supporting wall portion and defining a third chamber in front of said firstmentioned supporting wall portion into which one end ofeach of said reaction tubes open and also defining a uid passageway between one end of said heat exchange chamber and said third chamber, a combustion fluid inlet open to an opposite end of said heat exchange chamber, an enclosing portion in a spaced relationship along said second-mentioned supporting :wall portion and defining a fourth chamber in back of said second-mentioned supporting wall portion into which the other ends of said reaction tubes open, a plurality of combustion fluid inlets open to said third chamber, a, plurality of exhaust fluid outlets open from said fourth chamber, and feed fluid tubes extending through said fourth chamber and for a substantial distance within said reaction tubes.

5. Furnace apparatus suitable for continuously thermally converting iuid hydrocarbons comprising, a plurality of spaced-apart reaction tubes, each of said reaction tubes having a combustion fluid inlet opening at a front end thereof and an exhaust fluid outlet opening at a rear end thereof, an enclosure for said reaction tubes having a pair of supporting wall portions spaced along said reaction tubes and defining a heat exchange chamber about exterior walls of said reaction tubes, a front enclosure extending about and in a spaced relationship with front ends of said reaction tubes and defining a front chamber into which the combustion fluid inlet opening of each of said reaction tubes open, a rear enclosure extending about and in a spaced relation with the rear ends of said reaction tubes and defining a rear chamber into which the exhaust fluid outlet openings of each of said reaction tubes open, a plurality of combustion fluid inlet tubes extending through said front enclosure and open to said front chamber in a, spacedapart and substantially axially-aligned relationship with the combustion fluid inlet openings of each of said reaction tubes, a plurality of feed fluid tubes extending through said rear enclosure into said rear chamber and through the exhaust fluid outlet openings of and for a substantial distance substantially concentrically along said reaction tubes, and a plurality of substantially equal length exhaust iuid outlet tubes extending through said rear enclosure and open to said rear chamber.

6. Furnace apparatus as defined in claim 5 wherein, a cooling fluid inlet and outlet are connected to opposite end portions of said heat exchange chamber.

'7. Thermal apparatus suitable for continuously converting fluid hydrocarbons comprising, a reaction tube, said reaction tube having a combustion fluid inlet opening at one end thereof and an exhaust fluid outlet opening at the other end thereof, an enclosure having spaced-apart walls supporting said reaction tube and defining a heat exchange chamber about exterior walls of said reaction tube, an enclosure having a portion spaced from and extending about the combustion fluid inlet opening of said reaction tube and defining a front chamber about said reaction tube into which the combustion iiuid inlet opening of said tube opens, a fluid connection between an end of said heat exchange chamber and said front chamber, a combustion fluid inlet tube: extendingfthrouam said secondi-mentioned enclosureintofsad:frontichamber andlbeing` open thereto@ said =combustiorr fluid. inlet tube boing positioned'.I substantial: axial. alignmentfand in avspaced relationship-:With the. combustion duid inIetLopeninal of said Vreaction tube, avli'uidl inlet connection .throughL said Vrst-menti'cm'edY en-n closure into an opposite endfof/saidiheatex'- changezchamber-ffor introducing additional comk bnstionsnidsthrough. said heat.. exchange olfiainl ber.y andi saidV 'first-mentioned@ fluid-i connection into;v saidl front: chamber, andf a. supported: feedl uid inlet tube extending thnough the exhaust outlet;openingi of said: reaction-f. tube,A andbeing openi to;` the inside. of: saidrlreaction; tubeiapprox-i-i mately; intermediate thea combustion. fluids inletf. and;- exhaust iiuid outlet-openingsv ofiy said 1re actionstube.. s, Y

8i., Thermal:apparatusesuitable forsoontinaously;l converting; iiuidghydrocarbons comprising. ai rea action,Y tube; said; reactionzA tube, having; ai com'.-r bnstoniuidiiinletiopeningf,atione: end :.thereoliandi agi; exhaust. fluid.: outlet: openings `at the' otherf endrthereofl, segregatedisupporting..Wallsifor said; heactontube.; extending laterally' ofiisaid. reaotioni tiibesand, positionedV inf` a.; spacedapart, relation'- 251.111).. Y along; exterior Walls-ofi saidtu'be; and de -VV 'nlllg; as. Chambon!"therebetween-for the exterior` Wailla Q Said: tube;V an.; enclosuresv positioned; in; ai Sua ed;relation;y about.: the oombustioninuid-finlet,

ben into, which the.. combustion; fluid; inlet; sa: of: said reaction tube opens, a combos i. s d lnletfl tube extending through; said; en: closures into said; 1astmentioned chamber and.

bQI-ig fopen'thereto, a setondenQloSure positioned 1 ously thermally` converting, iuidv hydrocarbonsi comprisinga reactionftube, said reactionv tubes havinga combustioniiuid inlet -opening.; atr one y' end thereof and an exhausttfluid outletopening-g at the other endithero, wall portions supporting said reaction tube and having an enclosing portion in a spacedrelation about the combustion uid inletopeningofsaid reaction tube and dehing hainber into which the combustion fluidl inlet openingof said reaction tube opens, a combustion uid-inlettubehavinga smal'ler'diameter than said: reaction tube and being supported by andffextending through i saidi: enclosing:`v portion intousaid.'v chamber, the.. extending endiA lsaid combustionV iiuid i* inlet .tube beings opent. to said chamber and positief-ledA in substantial` `axial algnmentrand -ind a.. spaced Vrelationship with the combustion@ fiuid inletA` opening of said reaction tube;L refr'a'cztory` means positioned beyondv the combustion-iiiuidinlet openingfof and'iW-ithin saidf-reactiontube; said Wallportions having-#an enclosing portionV in Va -fspaced relation about the exhaust `flllli'd; outlet Aopening of 'saidreactioir tube anddei-ningga chamberintomwhich the exhaust and?4 a feed' fluid-inletY extendingf through said'` last-mentioned enclosing portion and for a substantial distance along and open to the inside of said reaction tube approximately intermediate s: f; Said; reaction, tubeV and deiiningi; a, o

the combustion1 ii'uidlinlet opening and the ex'- haust fiuid outlet openingV of said reaction tube at-a `position that isi'spaced from said refractory means' towardsthe exhaust: fluid outlet opening of! 'sai'dlreaot'on tube. A

10. Furnace!apparatusfsuitabie for continuou's'ly thermally Converting fluid'- hydrocarbons intoiotherliydiozcarbons ooniprisifng, areaction tube; 'said reactiontubeL having 'a' combustion uid inlet:'openingsy at?I oneV end'- thereof and an exhaust fluidi outlets Aatltlie l other end' thereof;` reiiraotory# porti()no2-po'sitimedl Within said reaction tube adacefnl'f' to aiidspanedfrhrthefcombustion uid inlet'opon-in'g of Asaid. reactiontube, afeed fluid tube o's'maller'diarneten than-said reaction tub'e lia-virlgar portionext'eiidingf through the exhaust fluid outlet? opening of said` reaction tube and'alongi-'saidreaction-tube for a substantialdistance and being operrto` the inside of said reactionf tube avia/- position Witl'iin,A saidl reaction tube thatispetweenssaidlrefractory portions and theexhaust fluidi outlet opening"` of said reaction tube, means-supportings'aid reaction tube andY said second-mentioned tubeinfthe relationship 'Se d'end Vand ai-iik enclosures i-'nay spaced ip Aaioclxutf the co'inbu'stion'- fluidJA inlet-v of "saidi reaction* tube and defining a er' ii'ito which 'the oombustioniuidl iril'e't openingv 'ofi-said? reactioni tube'- o'p'ens; ano.-E 'a5- conibiistin'iiiiA fluidi inlet through4 saidl enclosurej ihto-saitiich'ainbor. v Y Y 111';l Thferzo'oal apparatus* suitable'V for` continu`vA ousiSf oorivertingf fluid hydrocarbons/comprising; al reaction tube;J saidj react-ioni tubel'iaving` a*- comb'ustionifliid'inltfopening-iat oneierld thereof and''an exhaustfiluid-outlet opening atfthe'other end? theref supporting Walllportions' for said reaction; tube' and? having anenclosing portion extending4A in a'- i spaced irrelationlabout the" Conil-- bustiondfuidinlet opening o'f"'said reaction tubevv and defining iaioliaimlbr into which saidire'aetion" tube opens, a combustion fluid inlet-"tubeihaving': a' portion extending; nwardlif through; said enclosngportior'iinto'said jchanbersandbeing open tosaid ch'ainbe l pjo'rtionof said fluid inlt tube being positioned.1 ir'r substantial axial alignment and in ja' spaced ouston fluid t inletM opening" at" one 'end theife'off" andan exhaust "flf'uid outlet; opening` Q'atth'e' other" en'dthe'reof refractory irfeahs positioned within anoiimbe andjdennigta mixingeichamber intov Wliioh the, combustin' fluid` inl'e'tiopningl o5 said. reaction tube, opens, a pair Aof combustion fluid inlets i open: into`-- said mixing chanber, anda reaction h'ydrooarbon. feedfluid inlet` open lto saidsreaotiontubeat 'a .substantial "distancefrein`I the exhausts fluid-s openingl4 and Y approximately:

intermediasue@Gesamtsummeause exhaust uid openings thereof at a position within said reaction tube that is spaced between th'e i inwardly'- extending'l open# galateo l l said-refractory means and therexhaust fluid outlet opening of said reaction tube.

13. A thermal apparatus suitable for continuously converting fluid hydrocarbons comprising, a reaction tube having a combustion fluid inlet opening at oneend thereof and an exhaust fluid outlet opening at the other end thereof, supporting means for said reaction tube, spacedapart refractory portions within and about the inside of said reaction tube adjacent to and spaced from the inlet opening of said reaction tube, a feed fluid inlet tube positioned to extend through and a substantial distance from the exhaust fluid opening of and substantially concentrically along said reaction tube, said feed uid inlet tube being open to said reaction tube at a substantial distance from the exhaust fluid opening and aproximately intermediate the combustion fluid inlet and exhaust fluid openings thereof at a positionrwithin said reaction tube that is spaced from said refractory portions and towards the exhaust uid outlet opening of said reaction tube, and positioning means for said feed fluid inlet tube.

`14. Thermal apparatussuitable for continue ously converting fluid hydrocarbons comprising, a reaction tube, said reaction tube having a combustion fluid inlet opening at one end thereof and an exhaust fluid outlet opening at the other end thereof, refractory means positioned within 1 said reaction tube adjacent to and spaced from the inlet opening thereof, a reaction hydrocarbon feed fluid inlet extending through and along said f reaction tube and being open to the inside of said reaction tube at a substantial distance from the 1- exhaust fluid opening and approximately intermediate the combustion fluid inlet and exhaust fluid openings of said reaction tube at a spaced location from said refractory means and between said refractory means and the outlet opening of said reaction tube, and positioning means for said feed fluid inlet.

15. Thermal apparatus suitable for continuously converting fluid hydrocarbons comprising,

a reaction tube, said reaction tube having a combustion fluid inlet opening at one end thereof and an exhaust fluid outlet opening at the other end thereof, refractory means positioned within said reaction tube adjacent to and spaced from the inlet opening thereof, a feed fluid inlet open to said reaction tube at a substantial distance from the exhaust fluid opening and approximately intermediate the'combustion fluid inlet and exhaust fluid openings of said reaction tube at a spaced location from said refractory means and between said refractory means and the outlet opening of said reaction tube, positioning means for said feed fluid inlet, a wall positioned about the exhaust fluid outlet of said reaction tube so as to define a chamber into which said reaction smaller diameter than said reaction tube and Y having a portion extending for a substantial distance into and along said reaction tube through and from the exhaust fluid outlet opening of said reaction tube, said extending portion of said feed inlet tube being open to the insideof saidreactiontube `at a position Within said reaction tube that is spaced from said refractory portions and towards the exhaust ud outlet opening of said reaction tube, and means positioning said extending portion of said feed fluid inlet tube Within said reaction tube in a spaced relationship therealong with respect to the inner Walls of said reaction tube.

17. A furnace for converting normally gaseous hydrocarbons into other hydrocarbons comprising a plurality of horizontally extending reaction tubes supported by and positioned in separated refractory Walls, a first wall of said separatedA supporting Walls at one end of said tubes and a second of said walls together with said rstwall defining avertical passageway about the exterior portions of said tubes, a front enclosing Wall for the furnace separated from said first supporting Wall and extending so as to form a relatively narrow frontal chamber into whichsaid tubes open and which communicates adjacent a bottom end thereof and through said rst supporting Wall with said vertical passageway, aninlet into the top end of said vertical passageway, a third wall of said supporting walls at the opposite ends of said tubes, a rear enclosing wall for the furnace defining a relatively narrow rear chamber into which said tubes open, a plurality of inlets into. said first chamber, aV plurality of outlets from saidi rear chamber, and pipes extending through said: rear chamber and for `a substantial distance into.. said tubes and concentrically arranged therein.

18. A furnace as defined in claim 17, whereinsaid outlets have substantially V-shaped branch portions extending from said rear chamber, said branch portions being connected to-a common outlet portion. Y

19. A furnace as defined in claim 17, wherein each of said inlets into said rst chamber is a pipe portion positioned in a substantially axially aligned vrelationship with the front end of a corresponding one of said reaction tubes, and said reaction tubes are positioned in a spaced-apart relationship with respect to each other by said separated-refractory Walls.

JOHN B. ORR,JR.

REFERENOESy CITED rhe Vfollowing references are Yof record in the file of this patent:

H Uru'risn STATES PATENTS Y Date Number Y .Name

1,823,503 Mittasch et al Sept. 15, 1931 1,847,241 Gregory Mar. 1, 1932 1,847,242 Guyer et al Mar. 1, 1932 1,854,205 Lewis Apr. 19, 1932 1,880,309 Wulff Oct. 4, 1932 1,972,116 Waern Sept. 4, 1934 2,013,809 Salisbury Sept.` 10, 1935 2,039,981 Rembert May 5, 1936 2,129,269 Furlong Sept. 6, 1938 2,135,695 Bardwell Nov. 8, 1938 2,140,316 Furlong Dec. 13, 1938 2,221,583 Hoop Nov. 12, 1940 2,267,720 Cyr et al Dec. 30, 1941 2,292,355 Ayres Aug. 11, 1942 v2,368,828 Hanson et al Feb. 6, 1945 

1. A FURNACE FOR THEREMALLY CONVERTING NORMALLY GASEOUS HYDROCARBONS INTO OTHER HYDROCARBONS COMPRISING A PLURALITY OF HORIZONTALLY EXTENDING REACTION TUBES SUPPORTED BY AND POSITIONED IN SEPARATED REFRACTORY WALLS, A FIRST WALL OF SAID SEPARATED SUPORTING WALLS AT ONE END OF SAID TUBES AND A SECOND OF SAID WALLS TOGETHER WITH SAID FIRST WALL DEFINING A VERTICAL PASSAGEWAY ABOUT THE EXTERIOR PORTIONS OF SAID TUBES, A FRONT ENCLOSING WALL FOR SAID FURNACE SEPARATED FROM SAID FIRST SUPPORTING WALL AND EXTENDING SO AS TO FORM A RELATIVELY NARROW FRONTAL CHAMBER INTO WHICH SAID TUBES OPEN AND WHICH COMMUNICATES AT THE TOP THEREOF WITH SAID VERTICAL PASSAGEWAY, A THIRD WALL OF SAID SUPPORTING WALLS AT THE OPPOSITE ENDS OF SAID TUBES AND A REAR ENCLOSING WALL FOR THE FURNACE DEFINING A RELATIVELY NARROW REAR CHAMBER INTO WHICH SAID TUBES OPEN, A PLURALITY OF INLETS INTO SAID FIRST CHAMBER, AN INLET INTO THE BOTTOM OF SAID VERTICAL PASSAGE, A PLURALITY OF SMALL OUTLETS FROM SAID REAR CHAMBER AND PIPES EXTENDING THROUGH SAID REAR CHAMBER AND FOR A SUBSTANTIAL DISTANCE INTO SAID TUBES AND CONCENTRICALLY ARRANGED THEREIN. 